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{{chembox| verifiedrevid = 436130941| ImageFile = Nysted_Reagent.png| ImageSize = 120px| ImageName = Structural formula of the Nysted reagent| ImageFile1 = | ImageSize1 = 120px | ImageName1 = | IUPACName = cyclo-Dibromodi-μ-methylene[μ-(tetrahydrofuran)]trizinc| OtherNames = |Section1={{Chembox Identifiers| SMILES = Br[Zn]C[Zn]C[Zn]Br.C1CCCO1

correct|chemspider}}| ChemSpiderID = 21171210| InChI = 1/C4H8O.2CH2.2BrH.3Zn/c1-2-4-5-3-1;;;;;;;/h1-4H2;2*1H2;2*1H;;;/q;;;;;;2*+1/p-2/rC4H8O.C2H4Br2Zn3/c1-2-4-5-3-1;3-6-1-5-2-7-4/h1-4H2;1-2H2| InChIKey = CCTHTLJWXPUNGT-LIIURCMFAD

correct|chemspider}}| StdInChI = 1S/C4H8O.2CH2.2BrH.3Zn/c1-2-4-5-3-1;;;;;;;/h1-4H2;2*1H2;2*1H;;;/q;;;;;;2*+1/p-2

correct|chemspider}}| StdInChIKey = CCTHTLJWXPUNGT-UHFFFAOYSA-L

correct|??}}| CASNo = 41114-59-4| RTECS = }}|Section2={{Chembox Properties| Formula = C6H12Br2OZn3| MolarMass = 456.14 g/mol| Appearance = | Solubility = }}|Section7={{Chembox Hazards| ExternalSDS = External MSDS| MainHazards = Flammable, may form explosive peroxides and reacts violently with water| FlashPtC = -26.0| GHS_ref = }}|Section8={{Chembox Related| OtherCompounds = }} }}The Nysted reagent is a reagent used in organic synthesis for the methylenation of a carbonyl group. It was discovered in 1975 by Leonard N. Nysted in Chicago, Illinois. It was originally prepared by reacting dibromomethane and activated zinc in THF.Nysted, L.N. US Patent, 1975, 3 865 848. see Chem. Abstr., 1875, 83, 10406q. A proposed mechanism for the methenylation reaction runs as follows:(File:Nysted Reaction.png|frameless|center|A proposed mechanism for the Nysted olefination|411x411px)A similar reagent is Tebbe’s reagent.“Nysted Reagent.” Comprehensive Organic Name Reactions and Reagents. 2010; John Wiley and Sons, Inc. In the Nysted olefination, the Nysted reagent reacts with TiCl4 to methylenate a carbonyl group. The biggest problem with these reagents are that the reactivity has not been well documented. It is believed that the TiCl4 acts as a mediator in the reaction. Nysted reagent can methylenate different carbonyl groups in the presence of different mediators. For example, in the presence of BF3•OEt2, the reagent will methylenate aldehydes. On the other hand, in the presence of TiCl4, TiCl3 or TiCl2 and BF3•OEt2, the reagent can methylenate ketones. Most commonly, it is used to methylenate ketones because of their general difficulty to methylenate due to crowding around the carbonyl group. The Nysted reagent is able to overcome the additional steric hindrance found in ketones, and more easily methylenate the carbonyl group. In contrast to the Wittig reaction the neutral reaction conditions of the Nysted reagent make it a useful alternative for the methylenation of easily enolizable ketones.{{cn|date=February 2024}}There is little research on Nysted reagent because of the hazards and high reactivity and the difficulty of keeping the reagent stable while it is in use. More specifically, it can form explosive peroxides when exposed to air and is extremely flammable. Also, it reacts violently with water. These make this reagent very dangerous to work with.WEB,www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=AU&language=en&productNumber=381985&brand=ALDRICH&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F381985%3Flang%3Den, Nysted Reagent. MSDS No.381985, Sigma-Aldrich, April 3, 2009, JOURNAL, Aïssa, Christophe, Riveiros, Ricardo, Ragot, Jacques, Fürstner, Alois, Total Syntheses of Amphidinolide T1, T3, T4, and T5, Journal of the American Chemical Society, December 2003, 125, 50, 15512–15520, 10.1021/ja038216z, 14664598, JOURNAL, Paquette, Leo A., Hartung, Ryan E., Hofferberth, John E., Vilotijevic, Ivan, Yang, Jiong, Synthesis of Stereoisomeric Medium-Ring α,α’-Dihydroxy Cycloalkanones, The Journal of Organic Chemistry, April 2004, 69, 7, 2454–2460, 10.1021/jo0358675, 15049645, JOURNAL, Clark, J. Stephen, Fessard, Thomas C., Wilson, Claire, A Concise and Stereoselective Synthesis of the A-Ring Fragment of the Gambieric Acids, Organic Letters, May 2004, 6, 11, 1773–1776, 10.1021/ol049483s, 15151411, JOURNAL, Crich, David, Banerjee, Abhisek, Stereocontrolled Synthesis of the d - and l - glycero -β- d - manno -Heptopyranosides and Their 6-Deoxy Analogues. Synthesis of Methyl α- l - Rhamno -pyranosyl-(1→3)- d - glycero -β- d - manno -heptopyranosyl- (1→3)-6-deoxy- glycero -β- d - manno -heptopyranosyl-(1→4)-α- l - rhamno -pyranoside, a Tetrasaccharide Subunit of the Lipopolysaccharide from Plesimonas shigelloides, Journal of the American Chemical Society, June 2006, 128, 24, 8078–8086, 10.1021/ja061594u, 16771524, 2617734, See also Petasis reagent Titanium–zinc methylenation Wittig reaction References {{Reflist}}